Myocardial and renal arteriolar thickening in cigarette smokers.

Arteriolar wall thickness was measured in cigarette smokers by means of eyepiece micrometry, paper planimetry and computerized planimetry. Myocardial and renal arterioles in such smokers showed significant thickening of their walls. This thickening was mainly attributable to an increase in collagen and smooth muscle. The adventitia of small to medium-sized intramyocardial coronary arteries showed an increase in collagen. Platelets are known to be more adhesive to the vessel wall in smokers. It is suggested that platelet-derived growth factor, released in the vessel wall, may promote proliferation of connective tissues, thus leading to the vascular thickening described.